and here's president obama. let's listen. >> i've just been briefed by my national security team, including fbi director mueller. attorney general holder. secretary napolitano and my counterterrorism and homeland security adviser, lisa monacacm. we deploy all resource to investigate an respond to this attack. obviously our first thoughts this morning are with the victims. their families and the city of boston. we know that two explosions gravely wounded dozens of americans and took the lives of others including an 8-year-old boy. this was a heinous and cowardly act and given what we now know about what took place the fbi is investigating it as an act of terrorism. any time bombs are used to target innocent civilians, it is an act of terror. what we don't yet know, however, is who carried out this attack or why, whether it was planned and executed by a terrorist organization, foreign or domestic, or was the act of a malevolent individual. that's what we don't yet know. and clearly, we're at the beginning of our i